gulpfile.js

const gulp        = require( 'gulp' );
const sass        = require( 'gulp-sass' )( require( 'sass' ) );
const sourcemaps  = require( 'gulp-sourcemaps' );
const cleanCSS    = require( 'gulp-clean-css' );
const browserSync = require( 'browser-sync' ).create();
const file_system = require( 'fs' );
const uglify      = require( 'gulp-uglify' );
const pump        = require( 'pump' );
const wp_pot      = require( 'gulp-wp-pot' );

const update_assets_version = function () {
	file_system.writeFile( './assets/last_update', ( new Date() ).toISOString().replace( /[^0-9]/g, '' ), function ( error ) {
		if ( error ) {
			return console.log( error );
		}

		console.log( "The file was saved!" );
	} );
};

gulp.task( 'make_pot', function ( done ) {
	gulp.src( './**/*.php' )
	.pipe( wp_pot( {
		domain         : 'wp-plugin-domain',
		package        : 'WP Plugins Boilerplate',
		headers        : {
			poedit                  : true,
			'x-poedit-keywordslist' : true
		},
		lastTranslator : 'Nabeel Molham <n.molham@gmail.com>'
	} ) )
	.pipe( gulp.dest( './languages/template.pot' ) );

	done();
} );

gulp.task( 'styles', function ( done ) {
	gulp.src( [ './assets/src/css/**/*.scss', './assets/src/css/**/*.css' ] )
	.pipe( sourcemaps.init() )
	.pipe( sass().on( 'error', sass.logError ) )
	.pipe( cleanCSS( { compatibility : 'ie8' } ) )
	.pipe( sourcemaps.write( './maps' ) )
	.pipe( gulp.dest( './assets/dist/css/' ) )
	.pipe( browserSync.stream() );

	update_assets_version();
	done();
} );

gulp.task( 'compress_js', function ( done ) {
	pump( [
		gulp.src( './assets/src/js/**/*.js' ),
		uglify( {
			mangle : {
				eval : true
			}
		} ),
		gulp.dest( './assets/dist/js/' )
	], done );

	update_assets_version();
} );

const start_watch_assets = function () {
	gulp.watch( [
		'assets/src/css/**/*.scss',
		'assets/src/css/**/*.css',
		'style.css'
	], gulp.series( 'styles' ) );

	gulp.watch( [
		'assets/src/js/**/*.js'
	], gulp.series( 'compress_js' ) );

	gulp.watch( [
		'**/*.php'
	], gulp.series( 'make_pot' ) );
};

gulp.task( 'watch_assets', gulp.series( 'styles', 'compress_js', 'make_pot', function ( done ) {
	start_watch_assets();
	done();
} ) );

gulp.task( 'serve', gulp.series( 'styles', 'compress_js', 'make_pot', function ( done ) {
	browserSync.init( {
		proxy : "localhost"
	} );

	start_watch_assets();
	done();
} ) );